The present invention relates to a fuel injection valve which injects fuel into an internal combustion engine; and, more particularly, the invention relates to a technique for forming a fuel spray that has excellent atomization.
JP-A-10-43640 (1998), in particular page 2 and FIGS. 1 and 2 thereof, discloses one example of a conventional fuel injection valve, in which a valve body is provided with a valve seat at an inner wall face forming a fluid passage, a valve member for opening and closing the fluid passage by displacing a contacting portion thereof away from the valve seat and biasing the contact portion thereof into contact with the valve seat, respectively, and an orifice plate attached to the valve body at the fluid downstream side from the valve member and having an orifice penetrating the orifice plate in its thickness direction. The face of the orifice plate which faces the valve member, the end face of the valve member and the inner wall of the valve body form a substantially disk shaped fluid chamber in which an obstacle is provided for disturbing the fluid flowing from an opening, that is formed between the contacting portion and the valve seat, to the orifice.
The above-referenced patent document discloses as the obstacle for disturbing the fluid flow, the provision of an unevenness which is provided either on the end face of the valve member at the fluid flow downstream side from the opening portion between the contacting portion and the valve seat, or on the face of the orifice plate opposing the valve member.
In the above-described device, before the fuel reaches to the injection hole, a disturbance is caused in the fuel flow to make the particle diameter of the spray become small. However, in order to reduce fuel consumption effectively, or to reduce the exhaust amount of unburned gas components (HC,CO) of the fuel, further atomization of the spray is required.